Firefighters began to gain ground on Thursday against wildfires that have killed at least 31 people in Northern California and left hundreds missing in the pandemonium of mass evacuations in the heart of the state's wine country.

The latest casualty figures, revised upward by three fatalities on Thursday, marked the greatest loss life from a single California wildfire event in 84 years.

Authorities have warned that the death toll from a spate of more than 20 fires raging across eight counties for a fourth day could climb higher, with hundreds of people in Sonoma County alone still listed as missing.

Extreme wind conditions that had been forecast for Wednesday night and early Thursday failed to materialize, giving fire crews a chance to start carving containment lines around the perimeter of some of the blazes.

Some 8,000 firefighters hurried to extend those buffer lines before another bout of dry, gusty weather was expected to return this weekend across much the state, said Ken Pimlot, director of the California Department of Forestry and Fire Protection (Cal Fire).

Fire teams were "making progress" but were "a long way from being out of the woods," Pimlot said at a news conference in Sacramento, the state capital.

Mark Ghilarducci, state director of emergency services, added that: "We are not even close to being out of this emergency."

'YOU ARE ON YOUR OWN'

One of greatest immediate threats posed to population centers continued to be in the Napa Valley town of Calistoga, whose 5,000-plus residents were ordered from their homes on Wednesday night as winds picked up and fire crept closer.

Calistoga Mayor Chris Canning said anyone refusing to heed the mandatory evacuation would be left to fend for themselves if fire approached, warning on Thursday: "You are on your own."

The fires have scorched more than 190,000 acres (77,000 hectares) - an area nearly the size of New York City - and destroyed at least 3,500 buildings, reducing whole neighborhoods in the city of Santa Rosa to gray landscapes of ash, smoldering ruins, charred trees and burned-out cars.

The official cause of the disaster was under investigation, but power lines knocked down by gale-force winds may have sparked the conflagration.

Twenty-six people, all civilians, were confirmed dead, surpassing the human toll of California's second-deadliest blaze on record, a firestorm that claimed 25 lives as it swept the Oakland Hills east of San Francisco in October 1991. The 1933 Griffith Park fire in Los Angeles had the highest death toll of 29.

Fire officials have said some victims from the latest fires were asleep when flames engulfed their homes. Others had only minutes to escape as winds of over 60 mph fanned fast moving blazes. Ghilarducci said the loss of cellular communications towers likely contributed to difficulties in warning residents by mobile phone alerts.

"We have found bodies that were completely intact, and we have found bodies that were no more than ash and bone," Sonoma County Sheriff Rob Giordano told reporters. He added that recovery teams would begin searching ruins with cadaver dogs.

As many as 900 missing-persons reports had been filed in Sonoma County alone, although 437 have since turned up safe, Giordano said.

It remained unclear how many of the 463 still listed as unaccounted for might be actual fire victims rather than evacuees who failed to alert authorities after fleeing their homes, he said.

"The best we can pray for is that they haven't checked in," emergency operations spokeswoman Jennifer Larocque told Reuters.

The fiercest of the blazes, the so-called Tubbs fire, accounted for 14 of the fatalities, all in Sonoma County, making it the deadliest single blaze since 2003, according to state data.

SMOKE, ASH IN BAY AREA

About 25,000 people remained displaced on Wednesday as the fires belched smoke that drifted over the San Francisco Bay area, about 50 miles to the south, where visibility was shrouded in haze and automobiles were coated with ash.

The National Weather Service warned on Thursday morning of persistent "critical fire weather conditions" in the fire zone for the next three days, with no rain expected and dry winds from the north with gusts upward of 35 miles per hour (55 kph).

The Tubbs fire on Thursday was within 2 miles (3 km) of Calistoga, which had appeared to be in the path of advancing flames but was spared on the first night of the fires.

Whether the town burns "is going to depend on the wind," Calistoga's Fire Chief Steve Campbell told Reuters early on Thursday. "High winds are predicted but we have not received them yet."

New evacuations also were issued in Sonoma County late on Wednesday for parts of Santa Rosa, the largest city in the wine-producing region, and Geyserville, an unincorporated town of 800 people.

While the cause of the fires have not been determined, they are thought to have been sparked by power lines toppled by gale-force winds and fanned by arid winds that blew into Northern California toward the Pacific on Sunday night.

Wildfires have damaged or demolished at least 13 Napa Valley wineries, a vintners' trade group said on Tuesday.

In addition to high winds, the fires have been stoked by an abundance of thick brush left ready to burn by a dry, hot summer.

Firefighters began to gain ground on Thursday against wildfires that have killed at least 31 people in Northern California and left hundreds missing in the pandemonium of mass evacuations in the heart of the state's wine country.
The latest casualty figures, revised upward...